Shower base



FIG. 1 is a front perspective view of a shower base showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a side view of the opposite side of FIG. 4; and,

FIG. 6 is a top view thereof.

The shower base is shown with symbolic breaks in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design. 

CLAIM We claim the ornamental design for a shower base, as shown and described. 